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a) b - École Polytechnique de Montréal

a) b - École Polytechnique de Montréal

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One of the applications for porous biomaterial polymer blends is bone substitutions. The<br />

proposed polymeric scaffolds are able to stimulate the bone regeneration process and to induce<br />

the mineralization of the surrounding tissue. Scaffolds with high mechanical properties and high<br />

porosity can be prepared in or<strong>de</strong>r to produce scaffolds for load bearing applications (Figure 1-5).<br />

Figure 1-5. MIT and Cambridge University scientists <strong>de</strong>veloped this tissue scaffold that could<br />

help repair knees and other joints. The top section, indicated by the green arrow, stimulates bone<br />

growth, while the lower half, marked by the orange arrow, stimulates cartilage<br />

growth(http://web.mit.edu/newsoffice/2009/cartilage-0511.html)<br />

As well, hierarchical systems exhibiting a multi-level distribution of porosity can be wi<strong>de</strong>ly<br />

employed in tissue engineering applications. Polymeric scaffolds characterized by macro-pores<br />

(100-500 μm) and micro-pores (10-50 μm) are useful as carriers for mesoporous (2-10 nm) silica<br />

spheres (e.g. MCM-41), with the objective of loading them with drug molecules (ibuprofen).<br />

These three pore sizes are very important in drug <strong>de</strong>livery systems. Whereas macro-pores can be<br />

used for cell colonization and blood vessel access, micro-pores are necessary for the diffusion of<br />

nutrients/fluids insi<strong>de</strong> a graft, and meso-pores are exploited for drug uptake and release.<br />

5

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